The incidence of antinuclear antibodies (ANA) detected by indirect immunofluorescence assay (IFA) method.

Human anti-nuclear antibodies (ANA) in Systemic Lupus Erythematosus (SLE) react specificaly with DNA, RNA, several proteins and ribonucleoproteins. Systemic Lupus Erythematosus is the classic type of polysystemic autoimmune disease. The high frequency of ANA is determined in these patients. Actually, all SLE patients are ANA positive. ANA testing by IFA (Indirect Immunofluorescence Assay) is an excellent screening tool for SLE cases, but it is not so highly specific test. Patients with connective tissue diseases, such as rheumatoid arthritis, scleroderma and dermatomyositis are also frequently positive. Results of IFA ANA have relative low specific degree, and for this reason the titration of these specimens to the end point is usually recommended. Indirect immunoflourescence is reference method for ANA testing. Common substrates are thin sections of rodent organs or various types of cell lines. The cell line substrates are preferable to organ sections, because these rapidly dividing cells have higher level for detection of certain clinically relevant antigens such as (e.g., centromere, SSA (Ro) and Scl-70). In this paper we present the results evaluation of ANA incidence, detected by IFA in serum specimens of corresponding clinical patients, during 2005 and 2006.